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A238806 Number of n X 2 0..2 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the sum of elements above it, modulo 3. 1

%I

%S 3,8,15,25,39,58,83,115,155,204,263,333,415,510,619,743,883,1040,1215,

%T 1409,1623,1858,2115,2395,2699,3028,3383,3765,4175,4614,5083,5583,

%U 6115,6680,7279,7913,8583,9290,10035,10819,11643,12508,13415,14365,15359

%N Number of n X 2 0..2 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of the sum of elements above it, modulo 3.

%H R. H. Hardin, <a href="/A238806/b238806.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (1/6)*n^3 + (23/6)*n - 1.

%F Conjectures from _Colin Barker_, Oct 24 2018: (Start)

%F G.f.: (3 - 4*x + x^2 + x^3) / (1 - x)^4.

%F a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>4.

%F (End)

%e Some solutions for n=5:

%e ..0..0....0..0....2..2....0..0....0..0....0..0....2..2....2..2....0..2....0..2

%e ..0..0....0..0....2..1....0..0....0..2....0..2....2..1....2..1....0..2....2..1

%e ..0..2....0..0....0..0....2..2....0..2....0..2....0..0....0..2....0..0....2..2

%e ..0..2....0..0....0..0....2..2....2..1....0..0....0..0....0..2....0..0....0..2

%e ..2..1....2..2....0..2....0..0....2..1....0..0....0..0....0..0....2..1....0..0

%Y Column 2 of A238812.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 05 2014

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Last modified August 9 15:01 EDT 2022. Contains 356026 sequences. (Running on oeis4.)